Fuel pump



Aug. 17 1926.. 1,596,194

F. LANG FUEL PUMP Filed August 4, 1925 Patented Aug. 17, 1926.

FRANZ I JAN 'G, OI STUTTGART, GERMANY.

FUEL PUMP.

Application flledAuguat 4, ms, Serial li o/48,188, and in Germany April 1s, m.-

Fuel .pumps for combustion, powerenines with fuel injection are known in -'which, for regulating fuel injectedthe moment of opening an 5 overflow-valve is adjusted by the speed regulator. These pum' s are characterized by the feature, that a ug-or stop connected to the pump piston opens theoverflow-valve by means of a double lever shortly before the end of thesuction stroke so that said valve closes again only shortly after the beginning of the pressure stroke of the pump,

and that in the latter course of said presa d nozzle upon the sure stroke a second lug or stop, connecte to the pump piston or to the driving means of the same and being adapted'to be ad-.

justed by the speed regulator, again opens the valve.

The purpose of this arrangement is to feed in the desired moment of the injection the fuel in considerable quantity and with hi h'speed to the injection nozzle. econsequence of this per se desirable that at the closing of the injection nozzle the fuel' still present on the valve seat must be removed by force in order to enable at all the necessary rapid closing of .the nozzle-valve.

'Imcontradistinction to aim is however,

3 this. arrangement from fuel by means ofthe fuel pump according to the present invention always immediately before the closin of the valve, so that the nozzle can take its seat without being forced of first removing the fuel from said seat. Furthermore this construction enables in the most safe manner the regulation of'the feeding of very small quantities of fuel. \1

This purpose is mainly attained by arranging the overflow-valve to the suction space n the pressure pipe between pump pressure ,valve and by in ection valve and r part of the pump pressure stroke. Thereby the sur lus compressed fuel is operatively returne to the pump suction space always before the pump piston reaches its .upperdead center position, so that the fuel quan 5 tities present in the pressure pipeconstantlyreceive a pulsatin motion.

- The return. feed pressed fuel can beefiected by a spring-influe wijfyalv r-ranged axially above .or. belowiths fu lpump, by a separate piston the quantity of the .vide with a circular groove,

.idea of employing a the seat of the nozzle-valve shall be released 0 indicates the nozzle needle, opening said overflow-valve during the last any, desired 'boreof the .of t e surplus"com-- or by a piston formed by an extension of theump piston, said extension being proand. the guide space of said iston extension being connect'ed at one side to the pressure space and at the other side to the suction pipe and to the suction space of the fuel pump.

Further it may be mentioned, that combustion power .engines'are known, in which a partial draining or emptying of the fuel pipe is enabled by means of a, return flowvalve, however only in view of the fact that the retort pressure can act through the open liquid in the pipe.

As this present action does not take place, when the nozzle is closed, at first it must appear useless to. an expert to 1 provide an overflow-valve in fuel pumps for injection en 'nes with closed nozzle.

nly the exact knowledge of the pressure action in the fuel piping, namel the breathing of the same under the in uence of the motion proceedings has led to the return flow-valve in the mentioned manner also with closed nozzles and has rendered it possible to govern exactly the injecting operation-as wellin' regard to the time as also in regarditofthe quantity. 7 4

.In the accompanying drawing, which several forms of construction ofthe' subject matter-of my invention are illustrated.

Fig. 1 shows a vertical section of a fuel pump with the injection nozzle in the cylinder head.

' Figs.2 and 3 show two modifications, in

which the injection nozzle is omitted and.

Fig. 4 shows the adjustment of the pump piston, which'adjustment can be effected by the engine regulator or by hand. 4

In Fig. 1 a indicates the cylinder head, to which the nozzle body I) is rigidly-connected. which carries seat 12, upon which thelower part of a sprin the spring e ing omitted asimmaterial).

The fuel pump body f is provided with a suction valve and a pressure valve h of Known construction and is further provided in the extension of the iston i with an equalizing is reduced in cross-section behind the tightening surface byiturn ng, said valve being lifted by the piston before the latter reaches its dead center povalve In, whi

rests (the adjusting means be- I equalizing valve 70 is connected to the pressure pipe h of the pump 7". An arising excess pressure accordingly opens the valve is and effects partiallyfla draining or enipty-' ing of the pressure chamber. The overflowing fuel is subjected to the sucking action, while a further flow of the fuel is fully obviated.

In Fig. 2 the overflow-valve is connected between valve seat and suction space toa fairly'tight-fitting valve body 10', the stem of which also is partially turned down or reduced. When now the valve with the piston is suddenly lifted by the pump piston, a sucking action on the fuel present in the pressure pipe is produced. When the sprin l a ain tends to close the valve, the fue 'tric les down through the ve small intermediate space between the piston and the slide surface. The pipe m serves for the same purpose as in Fig. 1.

In Fig. 3 this piston is replaced by a simple extension of the piston z' with a circular groove 11 serving as a regulating edge, said groove being connected to the pressure pipe h by means of a second pipe 12. The mode of operation is the same, but the. production is more simple and economical.

. Fig. 4 illustrates the possibility of putting the before described devices preliminarily out of operation during the starting of the motor and of making the operation-of the fuel pump dependent of the regulator of the engine, when the condition of persistence of the latter has been reached, however it is also always possible to correct the operation of the fuel pump by hand. The fuel piston 'z' which is operated by any desired known cam or' eccentric devices, carries at the end, which is directed away from the pump a screw thread n and also a rigidly connected gear wheel 0. The thread 12. can be influenced on the tappet ide p by a tooth bar operated by the regu ator of thefmotor' or by hand. During the startin is still sufliciently istarit from the equalizing members is incase 1, k in case 2 and not sufliciently closing the circular groove 01 in case 3. The starting period is burdened by a somewhat I eaterqon'sumption of fuel, which however 1s materially lessened at the engagement of the regulator. The correction by hand is especially important in shipand traction-en 'nes, as with the first at the emersion of the propelling screw and of the motor the piston 2" ing opened when said with the latter at the disengagement of the agriculture implements the motor would doubtless run off and adjustment of the regu .lator is neither theoretically nor practically possible for. such widely difl'ering conditions of'use.

I claim: v 1. The combination, with an internal combustion-engine having a fuel pump ofthe piston type, said ump having an intake passage and a disc arge passage, of means 3. In a fuel pump. for fuel injection combustion power engines having a closedinjection nozzle, the combination of a pump piston, a suction valve, a delivery valve, means providing a communication between the delivery side ofthe delivery valve'and the suction side of the suction valve, said pump piston formed to provide valve means con trolling such communication.

4. In an internal combustion engine, a fuel pump having a piston,.a suction valve. a delivery valve, meansfor injecting fuel into the engine, a conduit connecting said delivery valve with said means, a second 7 conduit connected to said first mentioned conduit at a point between the delivery valve and such fuel injecting means and adapted to relieve the pressure on said first mentioned conduit at a predetermined time, said pump piston extending into and forming valve means controlling said second conduit.

5. In an internal combustion engine, a fuel pump having a piston provided with a groove, a suction valve, a delivery valve, a nozzle for injecting fuel into the engine, a conduit connecting said delivery valve with said nozzle, a second conduit connected to said first mentioned conduit to release the pressure in said first mentioned conduit at a predetermined time, said second conduit bemg normally blocked by said piston but begroove is brought into register with said second conduit.

6. In an internal combustion engine, a fuel pump having a piston, a suction valve, a-

pressure valve, a fuel injection nozzle, a pressure condmt connecting said pressure valve and said injection nozzle, said pump piston formed to provide an overflow valve connected to said conduit between the pres: sure valve and the injection" nozzle, said overflow valve connected to the pump suction ipe and adapted to be opened durin the ast part of the pump pressure stro e in order to return surplus compressed fuel from the pressure conduit to the suction pipe beforethe pump completes its pressure stroke. 7. In an internal combustion engine, a fuel pump having a piston, an injection nozzle, a conduit connecting the pressure side of said pump to said nozzle, said pump piston providing Valve means connected. to said conduit, said valve means normally operable I to release the pressure in said conduit during the last part of the pressure stroke of. the pump, and means for axially adjusting the pump piston whereby the limits of the strokeof the piston are changed without changing the length of said stroke.

8. In an internal combustion engine, a

fuel pump having a piston, a suction valve, a

connected to said conduit between the pres- 7 sure valve and the injection nozzle, said overflow valve connected to the pump suction pipe and adapted to be opened during the last part of the pump pressure stroke in order to return surplus compressed fueLfrom the pressure conduit to the suction pipebefore the pump completes its pressure stroke, and means for regulating the operation of said overflow valve.

In testimony whereof FRANZ LANG.

I have hereunto 

